Background: This article describes the lessons learned from an international pilot assessment using the first version of the HTA Core Model® and Guidelines for rapid Relative Effectiveness Assessment (REA) of pharmaceuticals based on input from three different perspectives: the assessors, the users (health technology assessment organisations) and the marketing authorisation holder.

Methods: A pilot assessment was performed of pazopanib for the treatment of advanced or metastatic renal cell carcinoma for which 54 individuals from 22 EUnetHTA member organisations from 16 European countries gave their contribution. The work was divided in eight domain teams. Subsequently, results of these domain teams were synthesised in one pilot report. Feedback on the outcomes of the pilot was gathered throughout the project and through structured surveys.

Results: The first version of the assessment was produced in six months and consisted of 55 question and answer pairs, 8 domain reports and a synthesis section that combined the results from the different domains. The organisation of the pilot required intense coordination. Main points of criticism on the assessment were the lengthiness of the document and overlap of information throughout the assessment.

Conclusions: A reduction in the number of authoring organisations and individuals participating is necessary to avoid information overlap and increase efficiency in undertaking the assessment. Involving several organisations (e.g. five) in an in-depth review could still ensure the benefit of broad participation from various countries. The focus of a rapid REA should be on the first four domains of the Model.